fix: FollowTarget enum — actor_url no longer lies about holding a handle

FollowCommand.target is now FollowTarget (Identity|Handle) instead of
SocialIdentity. actor_url field always holds a URL; handles go through
FollowTarget::Handle. Adapter resolves handles explicitly. Type system
prevents misuse in future commands.

crates/domain/src/events.rs

@@ -65,7 +65,7 @@ pub enum DomainEvent {
     },
     FollowRequested {
         follower: UserId,
-        target: crate::value_objects::SocialIdentity,
+        target: crate::value_objects::FollowTarget,
     },
     FollowAccepted {
         owner: UserId,

crates/domain/src/ports/noop.rs

@@ -41,7 +41,7 @@ pub struct NoopSocialCommand;
 
 #[async_trait]
 impl super::SocialCommand for NoopSocialCommand {
-    async fn follow(&self, _: &UserId, _: &SocialIdentity) -> Result<(), DomainError> {
+    async fn follow(&self, _: &UserId, _: &crate::value_objects::FollowTarget) -> Result<(), DomainError> {
         Ok(())
     }
     async fn unfollow(&self, _: &UserId, _: &SocialIdentity) -> Result<(), DomainError> {

crates/domain/src/ports/social.rs

@@ -7,14 +7,14 @@ use crate::{
         DiaryEntry, FederationFlags, RemoteActorInfo, RemoteGoalEntry, RemoteWatchlistEntry,
         WatchlistWithMovie,
     },
-    value_objects::{MovieId, SocialActor, SocialIdentity, UserId},
+    value_objects::{FollowTarget, MovieId, SocialActor, SocialIdentity, UserId},
 };
 
 // ── Unified social ports (ADR-0002) ─────────────────────────────────────────
 
 #[async_trait]
 pub trait SocialCommand: Send + Sync {
-    async fn follow(&self, follower: &UserId, target: &SocialIdentity) -> Result<(), DomainError>;
+    async fn follow(&self, follower: &UserId, target: &FollowTarget) -> Result<(), DomainError>;
 
     async fn unfollow(&self, follower: &UserId, target: &SocialIdentity)
     -> Result<(), DomainError>;

crates/domain/src/testing/in_memory.rs

@@ -893,8 +893,18 @@ impl InMemorySocialRepository {
 
 #[async_trait]
 impl SocialCommand for InMemorySocialRepository {
-    async fn follow(&self, follower: &UserId, target: &SocialIdentity) -> Result<(), DomainError> {
-        if let SocialIdentity::Local(target_id) = target {
+    async fn follow(
+        &self,
+        follower: &UserId,
+        target: &crate::value_objects::FollowTarget,
+    ) -> Result<(), DomainError> {
+        let identity = match target {
+            crate::value_objects::FollowTarget::Identity(id) => id.clone(),
+            crate::value_objects::FollowTarget::Handle(h) => SocialIdentity::Remote {
+                actor_url: h.clone(),
+            },
+        };
+        if let SocialIdentity::Local(target_id) = &identity {
             if follower == target_id {
                 return Err(DomainError::ValidationError(
                     "Cannot follow yourself".into(),
@@ -904,11 +914,11 @@ impl SocialCommand for InMemorySocialRepository {
         let mut store = self.follows.lock().unwrap();
         let already = store
             .iter()
-            .any(|(f, t, _)| *f == follower.value() && t == target);
+            .any(|(f, t, _)| *f == follower.value() && *t == identity);
         if already {
             return Err(DomainError::ValidationError("Already following".into()));
         }
-        store.push((follower.value(), target.clone(), FollowState::Pending));
+        store.push((follower.value(), identity, FollowState::Pending));
         Ok(())
     }
 

crates/domain/src/tests/events.rs

@@ -1,5 +1,5 @@
 use super::*;
-use crate::value_objects::{SocialIdentity, UserId};
+use crate::value_objects::{FollowTarget, SocialIdentity, UserId};
 
 #[test]
 fn follow_accepted_matches() {
@@ -22,17 +22,33 @@ fn follow_accepted_matches() {
 }
 
 #[test]
-fn follow_requested_local() {
+fn follow_requested_with_identity() {
     let follower = UserId::from_uuid(uuid::Uuid::new_v4());
     let target = UserId::from_uuid(uuid::Uuid::new_v4());
     let event = DomainEvent::FollowRequested {
         follower: follower.clone(),
-        target: SocialIdentity::Local(target.clone()),
+        target: FollowTarget::Identity(SocialIdentity::Local(target.clone())),
     };
     assert!(matches!(
         event,
         DomainEvent::FollowRequested {
-            target: SocialIdentity::Local(_),
+            target: FollowTarget::Identity(SocialIdentity::Local(_)),
+            ..
+        }
+    ));
+}
+
+#[test]
+fn follow_requested_with_handle() {
+    let follower = UserId::from_uuid(uuid::Uuid::new_v4());
+    let event = DomainEvent::FollowRequested {
+        follower: follower.clone(),
+        target: FollowTarget::Handle("@alice@remote.example".into()),
+    };
+    assert!(matches!(
+        event,
+        DomainEvent::FollowRequested {
+            target: FollowTarget::Handle(_),
             ..
         }
     ));

crates/domain/src/value_objects/social.rs

@@ -16,6 +16,12 @@ impl SocialIdentity {
     }
 }
 
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub enum FollowTarget {
+    Identity(SocialIdentity),
+    Handle(String),
+}
+
 #[derive(Clone, Debug)]
 pub struct SocialActor {
     pub identity: SocialIdentity,